Introduction to Rectifier
Rectifier: is a thyristor (power electronic power devices) as the basis, to intelligent digital control circuit as the core of the power power control appliances. With high efficiency, no mechanical noise and wear, fast response, small size, light weight and many other advantages.
The rectifier is a commonly used power semiconductor electronic device with the ability to control the switch several kilowatts or even megawatt-class electric power. Structurally, it is a reverse-cut triode-type thyristor consisting of three PN junctions (PN -PN four layers.) The external lead of the device has cathode, anode, control electrode three electrodes, typical high current rectifier schematic section shown in Figure reverse polarity (anode negative) and PN junction diode reverse characteristics Similar to its positive characteristic, in a certain range of devices in a very high impedance state (positive blocking state, that is, the volt-ampere characteristics of a quadrant in the dashed line under the solid line.) When the forward instantaneous voltage is greater than the turn voltage , The device quickly changes to low-voltage high-current conduction state.
In the case of a positive blocking state, the device can be quickly energized to the on-state if the low-power trigger signal (the gate-cathode PN junction is turned on) is given to the control electrode, and then the trigger current Maintained in the conduction state, at this time if the current down to the maintenance current (volt-ampere characteristics of the dotted line) below, the device can be restored to the blocking state.
Rectifier: The main circuit using three-phase bridge or double reverse star with a balanced reactor circuit. SCR components using high-power components, energy-saving significantly. The main control system uses large board high threshold anti-interference, large-scale integrated control board; modules and integrated components are all imported, high reliability. With automatic voltage regulator, steady flow, stability accuracy is better than 1%. With 0 ~ 60S soft start, plating oxidation coloring time can be arbitrarily set, automatic timing. Using multi-phase rectifier to reduce the output voltage ripple factor ru, especially adapted to the hard chrome plating process, the surface finish is good, even the coating thickness. Cooling: water-cooled, air-cooled, since the cold.
Thyristor full name crystal thyristor, also known as thyristor: is a power semiconductor devices. It has a large capacity, high efficiency, good controllability, long life and small size and many other advantages, is weak control and charged between the strong electric bridge. From the energy point of view, power electronics technology known as the new electrical technology. China's energy efficiency is low, according to the national production yield energy consumption calculation, China is 4.98 times in France, Japan 4.43 times, so the thyristor as the core of the universal use of electrical control device is an important energy conservation in China is an important Measures.
The four-layer structure of a thyristor is usually described as a quadruple structure of a thyristor as an interconnection of NPN and PNP transistors. If the common-base current amplification coefficients of the two transistors are α1 and α2, respectively, as a function of the operating state The necessary condition is α1 + α2≃1. In the blocking state, the current amplification coefficient of the two transistors is very small; if the forward blocking state, in the control electrode into a forward current, the NPN tube current amplification factor α1 Rapidly increasing, and leads to an increase in α2, thus satisfying the conduction condition.
SCR is a very important power electronic devices, can be a very small control of the power control of megawatt-class power, commonly used in rectification, switching, frequency conversion, inverter and other circuits. High power SCR with a very large area Wafers, need to be packaged in a tube with a radiator.